SR. HR Business Partner III 401k, Payroll

MOBIS

Fountain Valley, CA Posted October 22, 2026

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On-site Full-time Senior
Job Description

Job Purpose The Senior HR Business Partner overseeing 401k, Expat Payroll, and Wellness will play a critical role in both the strategic development and operational management of employee benefits programs. This role ensures the effective administration of 401k plans, expatriate payroll processing, and wellness initiatives, while also aligning these programs with organizational goals and compliance requirements. The Senior HRBP will work closely with leadership and HR teams to drive improvements in financial offerings, and payroll efficiency, while ensuring full compliance with company policies and relevant regulations. Additionally, the Senior HRBP will serve as a backup for bi-weekly payroll, manage the day-to-day operations of the HRIS and Time/Attendance systems, and oversee the administration and design of group 401(k) retirement plan The role combines both operational responsibilities and strategic program oversight to ensure the efficient and accurate administration of payroll and 401(K) retirement plan. Key Accountabilities

  • Serves as the administrator of the company’s 401(k) plan, ensuring compliance with federal and state regulations. Works with external vendors and internal teams to manage plan operations, employee enrollments, contributions, and distributions. Analyzes 401k plan performance and provides recommendations for enhancing employee participation and engagement. Works closely with leadership to align the 401k plan with the company’s overall benefits strategy. 60%
  • Manages expatriate payroll processing, ensuring accuracy and compliance with global tax laws and company policies. Works with global payroll teams and external vendors to ensure smooth payroll operations across multiple regions. Provides guidance to expatriate employees on payroll-related issues and tax implications, while staying current on global payroll trends and regulations. Serves as the backup for Corporate Payroll. 40% Key Performance Indicators
  • Calculates normal and complex payrolls, including required and elected deductions/withholdings, corporate and regional incentive pay, and other processed earnings. Ensures Expatriate salaries are processed monthly, and necessary data is obtained to enter salary information timely. Serve as the back up for the Corporate Payroll. Makes changes to payroll files, processes corrections, and reviews timesheet data. Interfaces with all departments on payroll-related matters, such as benefit accruals, employment verification, time clock installations, and end-user system training, while being able to process both bi-weekly and monthly payrolls. Maintains data in the HRIS and Time/Attendance system for current employees, new hires, and terminations, and creates and updates reports based on system data. Regular tasks include creating reports to reconcile adjustments against payroll reports, ensuring proper deductions are reflected in employee records, and generating customary reconciliation reports, including 401(k), accumulators, vacation accruals, and month-end reports for the Finance department and HR Executive Coordinator. 40%
  • 401(k) Administration: Ensures proper handling of enrollments, terminations, changes, beneficiaries, calculations and compliance testing. Ensures maintenance of employee benefit files and updating of employee payroll records is taking place in Fidelity and ADP. Assists in the administration of wellness programs and activities designed to improve employee health and well-being. Recommends changes and/or additions to programs that reflect the changing needs of the employees. Assists with the administration of general benefits. 30%
  • Evaluation, Measurement, and Audit: Audits the accuracy and performance of the 401(k) and , analyzing usage, services, coverage, effectiveness, cost, and plan experience. Reviews competitive trends in these programs to assess the company’s stance. Performs audits, preparing, collecting, and organizing data for actuarial assessments. Reviews data in collaboration with actuarial evaluations, considering both short- and long-term cost projections. Surveys industry trends, completes relevant surveys, and analyzes the results to gain insights. Forecasts trends and assists in designing future program changes. Develops recommendations for management review, monitors the administrative costs of the programs, and recommends cost containment strategies. Prepares budget recommendations and helps monitor, verify, and reconcile budgeted funds. 20%
  • Cross-Functional Support: Addresses employee inquiries related to payroll matters, providing timely and accurate responses. Prepares ad-hoc reports and manages special projects that directly impact Payroll operations. Assists with document reporting requests for both HR and Finance audits. Additionally, handles requests from management, such as overtime and labor cost reports, and processes employment verification letters and vendor maintenance. Conducts research to identify enhancements to the HRIS system and 401k record keeper, ensuring its optimal utilization to support the department’s needs. 10% Major Challenges and Key Decisions
  • Payroll -
  • Interface with employees across the organization, responding to requests in a timely manner through in-person, email, or phone communication.
  • Collaborate with the ADP vendor to investigate discrepancies and provide information in non-routine situations. Ensure timely corrections are made and documented within periods defined in the plan document.
  • Oversee the process of payroll, ensuring compliance with wage and hour laws, reviewing employee hours worked, authorized deductions, and preparing related reports and records. Ensure timely payroll processing by scheduling non-emergency time off in advance.
  • Handle all employee verification requests.
  • Ensure the accurate interface of data between HRIS, payroll, time/attendance systems, and reporting modules, maintaining system integrity.
  • Conduct regular audits of payroll and payroll syncs with other systems to maintain accuracy.
  • Perform additional duties as assigned.
  • Keep management informed of any payroll-related issues in a timely manner and address any concerns that arise.
  • 401(k) -
  • Manage 5500 reporting and ensure the timely completion of all required filings.
  • Oversee annual discretionary funding for 401k programs.
  • Develop communication tools to enhance understanding of the company's 401(k) plan, including strategies to increase participation rates.
  • Serve as a participant on the 401(k) Fiduciary Committee, coordinating with the Plan Advisor to schedule and hold regular meetings, and overseeing activities to ensure compliance with fiduciary obligations, including timely publication of minutes.
  • Create and conduct presentations for management, employees, and field staff on the 401(k) plan, using audiovisual tools like PowerPoint and videos.
  • Provide customer service support to internal and external customers, developing and distributing materials such as orientation packets and summary plan descriptions for the 401(k) plan. Work Schedule and Travel Requirements Work Schedule Monday - Friday 8:00 AM - 5:00 PM; Flexible Schedule at the discretion and approval of Manager Travel Required No
Required Skills
human resources payroll compliance leadership HRIS tax KPIs cost estimation reconciliations month-end close testing ADP audit collaboration cross-functional collaboration communication
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